Rotary pump



NOV. 16, 1954 w SEAVEY 2,694,367

ROTARY PUMP Filed Nov. 1. 1950 2 Sheets-Sheet l United States Patent 2,694,367 ROTARY PUMP Robert W. Seavey, Tauuton,.Ma'ss. .assig nor ;to ,Para gon Gear Works, Inc, Tauuton, Mass., a corporation of Massachusetts Application November 1, 1 950;'ser,ia1lNo; 193,425"- 2 Claims. 01; 103-426 My invention relates to rotary pumpsof the' typ'e coniprising eccentrically related inner and outer rotors having intermeshing gear teeth. In its most particular'aspeet the invention is concerned with rotary pumps of the indicated class comprising a barrier elementmediate the rotor teeth and in which the'fluid intake and discharge are'in directions axial rather than peripheral avith relation to the rotors. I

My invention finds utility, for example, as .appliedto rotary crescent pumps adapted for useiiir hydraulic.transmission assemblies employed in association with marine engines. Such engines, as is'we'llkn'own, are manufactured in both right-hand andleft-handimodels, since'inthe case of twin screw vessels it is advantageous .to the end of avoiding an undesirable torque effect to provide for rotationof the screws in opposite directions. Thepre'sent practice of manufacturing the pumps in corresponding rightand left-hand models is'unduly' costly and is further unsatisfactory because' it necessitates the' carrying .of an inordinately large stock' of the pumps if requisitions therefor are to'be promptly filled; v

The present invention'provides a pump which is" suitable for use in either type tof'te'ng'ine; The pump is distinguished in that the component parts are so formedand related'that through simple rotative adjustmenhof certain of the parts the direction of flow of; the fluid 'm'edium through the pump may be mainta'inedthe same" irrespective of the direction of rotation of the rotors.

Generally described, my pump, as assembled, comprises a cover member having intake and discharge ports of arcuate shape for the fluid being pumped, a housing confining the rotors, and a seal plate mediate the rotors and the face of the cover member presenting the ports havin a pair of arcuate apertures therein, each of which is in registry with one of the ports and with an area of nonengagement or partial engagement of the teeth of the rotors, such area representing either the intake or discharge chamber of the pump.

The parts which are adjustable to the end that the direction of flow through the pump is maintained the same whether the rotors are driven clockwise or counterclockwise are the seal plate and the housing. In the event the pump is of the barrier type, the barrier is either fixed to the housing or is formed as an integral part thereof.

With the parts arranged as required according to the invention, the necessary adjustment in the event the pump drive is reversed consists simply of disconnecting the seal plate and the housing from the cover member, turning these parts relative to the cover member a predetermined like degree in their own planes and reconnecting them to the cover member. In the reassembled pump, the apertures in the seal plate are reversed with respect to the ports in the cover member.

My invention will be better understood through refer ence to the accompanying drawings illustrating the same in its preferred embodiment. In the drawings,

Fig. 1 is an end view of the pump assembly;

Fig. 2 is a section on the line 22 of Fig. 1; and

Figs. 3 and 4 are sections on the lines indicated in Fig. 2.

The pump illustrated is afiixed to its support by bolts which pass through holes 12 spaced around the outer margin of the cover member 10. The inner face of this member is formed to provide an annular recess within which a portion of the rotor housing 14 is received. Such housing is secured to the cover member via screw bolts 16 extending through apertures 18 into threaded holes in the cover member.

2,694,367 P 'atented Nov. 16, 1954 The central opening in-the cover member 10 within which the pump driveshaft (not shown) revolves is fitted with a-conventional oil seal 20. A keyway 24 serves in the connection of the pump drive shaft to the inner externally toothed rotor '22. The toothed portion of this rotor and the outer internally toothed driven rotor 26 are confinedin an annular recess 28 in the rotor housing, While that portion 29 of the inner rotor which is not provided with the teeth turns in the central shaftopening of .thefhousing.

Fixed toor, more preferably, integral with the housing 14' is a barrier member 25, shown as having the conventional crescent shape. The barrier extends in a direction toward the cover member 10 a distance corresponding to the axial length or thickness of the outer rotor and the toothed :portion of the inner rotor, the face of the barrier thus .being coplanar with the inner faces of the rotors.

two .ports Y30 and 32 which connect via passageways 34 and .36, respectively, with threaded openings 38 and 40,

respectively, below the ports. Opemng 38 is formed to receive .a complementarily threaded fixture fitted to the line through which the hydraulic fluid enters the pump, while opening 40 is adapted to receive a like fixture fitted t0 the line through which the hydraulic fluid is discharged.

Betweenthe ports 30 and 32 and the rotors is an annular seal plate 42 having arcuate apertures 44 and 46 therein. This plate is fastened to the cover member by means of .the previously mentioned screw bolts 16, the plate being provided with a series of marginal holes 56 through which the screw bolts pass. With the pump assembled, as shown, in anticipation of clockwise rotation of the drive shaft, aperture 44 is in registry with the upper portion of the port .30 and with the intake chamber 54, this chamber being represented by the area of'non-engagement of the rotors above the left-hand tip of the crescent barrier 25 as thesame appears in Fig. 4, while the aperture 46 is in registry with the upper portion of the port 32 and with the discharge chamber 52, .i. e. ,;the area of non-engagementof Ithe teeth'beyond the right-hand tip of the barrier member.

The central angle intercepting the are of the apertures 44, 46 corresponds substantially to the central angle intercepting the arc of the chambers 52, 54, which angle is somewhat less than half the central angle intercepting the arc of the ports 30, 32. The latter, except for the partitions 48 and 50, form a complete circle.

To facilitate assembly and adjustment of the pump, the seal plate and the housing 14 are each provided with direction arrows and with legending indicating the proper position of these parts as determined by the direction of rotation of the pump drive shaft.

In operation of the pump with the rotors rotating clockwise as indicated by the arrows (Figs. 1 and 3), the hydraulic fluid is drawn into the chamber 54 (Fig. 4) from the port 30 through the aperture 44 and is discharged from the chamber 52 through the aperture 46 and the port 32, ultimately leaving the system via the line, not shown, connecting with the pump at 40. As in the case of any such pump the hydraulic fluid is drawn into the pump by the vacuum resulting from the parting of the rotor teeth as they approach the crescent barrier and is discharged by the squeezing action of the teeth as they come together on losing contact with the barrier.

It will be readily seen that to adapt the pump for lefthand rotation it is only necessary to remove the screw bolts by means of which the seal plate and housing are fastened to the cover member and to rotate these parts so that aperture 46 is placed in registry with the lower portion of the port 30 and so that aperture 44 is placed in registry with the lower portion of the port 32. With the parts thus related, the hydraulic fluid is drawn into and discharged from the same sides of the pump as before.

Although I consider my invention particularly valuable as applied to rotary gear pumps comprising a barrier element, it will be readily apparent to those skilled in the art that it may be applied with equal advantage to pumps in which the gear teeth are of such shape as to do away with the necessity for a barrier. In such case the rotative ad- "'justment of the housing or equivalent part operates just I -as in the instance of the embodiment of the mventron above described, to change the location of the eccentricity of the rotors or gears as required to maintain the flow through the pump unchanged.

The reference herein to hydraulic transmissions is not to be taken as in any way limitative. It is further to be understood that the invention is not limited to a construction in which the driving rotor is the inner rotor, since in some installations it is more advantageous to make the outer rotor the driving rotor.

Having thus described and illustrated my invention, what I claim is:

1. A rotary gear pump having an inner toothed rotor mounted for rotation, a cover member having an inlet and an outlet port each extending substantially 180 along the periphery of said rotor, an outer annular toothed rotor mounted for rotation eccentrically of said inner rotor and intermeshing therewith along a portion only of its periphmeshing portions of said rotors, a seal plate disposed between said rotors and the ports of said cover member, said seal plate having a pair of arcuate apertures opening to the zones between said rotors at each end of the crescentshaped barrier member respectively, each aperture communicating with one port of the cover member, said housing, barrier member, and seal plate being releasably secured to said cover member; said housing, barrier member, and seal plate being freely rotatable as a unit with said rotors when released whereby each said aperture together with its corresponding zone between said rotors may be secured in communication with the other of said ports so that the direction of flow through said ports will remain the same when the direction of rotation of said rotors is reversed.

2. A rotary gear pump comprising an inner toothed rotor mounted for rotation, a cover member for said rotor having an inlet port and an outlet port each extending substantially 180 along the periphery of one side of said rotor, an outer toothed rotor mounted for rotation eccentric to the first said rotor and intermeshing therewith along o a portion only of its periphery to define an output zone where said rotating teeth approach each other to mesh 1 and an input-zone where said-teeth diverge aftermeshing,

a generally annular housing disposed at the side of said rotors opposite said cover-member, said housing being mounted concentrically with respect to one of said rotors and having an eccentric aperture in which the other of said rotors rotates, a seal plate disposed between said rotors and said cover member over the ports thereof and having a pair of apertures opening to said input and output zones respectively, each aperture communicating with one of said ports, and means for detachably securing said housing and seal plate to said cover member; said housing and seal plate being rotatable as a unit with said rotors when said securing means is detached whereby each said aperture together with its corresponding input and output zone may be secured, after rotation through approximately 180, in communication with the other of said ports so that the direction of flow through said ports will remain the same when the direction of rotation of said rotors is reversed, thus converting said input zone to an output zone and vice versa.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 1,660,464 Wilsey Feb. 28, 1928 1,700,818 Wilsey Feb. 5, 1929 1,719,640 Wilsey July 2, 1929 1,739,139 Haight Dec. 10, 1929 1,773,211 Wilsey Aug. 19, 1930 1,964,330 Pitt June 26, 1934 2,107,152 Huber Feb. 1, 1938 2,151,482 Neeson Mar. 21, 1939 2,302,907 Eilers Nov. 24, 1942 2,364,469 Orr Dec. 5, 1944 2,373,368 Witchger Apr. 10, 1945 2,490,391 Wentling Dec. 6, 1949 2,565,077 Holl Aug. 21, 1951 FOREIGN PATENTS Number Country Date 415,425 Germany June 19, 1925 594,214 Great Britain Nov. 5, 1947 

